1. Field of the Invention
The present invention relates to a gas insulation circuit breaker with a structure for reducing friction, and particularly, to a gas insulation circuit breaker capable of extinguishing an arc by blowing arc-extinguishing gas to a space between a fixed arc contactor and a movable arc contactor at the time of a circuit breaking operation.
2. Background of the Invention
FIG. 1 is a gas insulation circuit breaker in accordance with the conventional art, which shows a structure of a circuit breaking portion, and FIG. 2 is a view showing an operational state of the circuit breaking portion of FIG. 1.
As shown, the circuit breaking portion of the conventional gas insulation circuit breaker consists of a fixed side and a movable side.
The fixed side consists of a first fixed contactor 1 and a fixed arc contactor 2.
The movable side consists of a second fixed contactor 3, a movable contactor 4 movably installed in the second fixed contactor 3, a fixed piston 5 installed in the movable contactor 4 and forming a compression chamber 6, a movable arc contactor 7 connected to or separated from the fixed arc contactor 2 by being moved together with the movable contactor 4, a nozzle 8 fixed to the movable contactor 4, and a connection rod 9 configured to connect a rod 10 of the movable contactor 4 to a manipulation unit (not shown) of a circuit breaker.
In a case that the circuit breaker is in a normal conductive state, as shown in FIG. 1, the movable arc contactor 7 is connected to the fixed arc contactor 2, thereby maintaining a closed circuit.
In this state, if the circuit breaker is tripped, force is transmitted to the connection rod 9 connected to the manipulation unit in a right direction (opening direction), and thus a trip operation of a high speed is started. And, the movable contactor 4 connected to the connection rod 9 by the rod 10, and the movable arc contactor 7 are moved together toward a moving direction of the connection rod 9.
Here, a capacity of the compression chamber 6 formed by the movable contactor 4 and the fixed piston 5 is drastically decreased as the movable contactor 4 is moved. Upon separation of the movable arc contactor 7 from the fixed arc contactor 2 due to movement of the movable contactor 4, an arc occurs between the movable arc contactor 7 and the fixed arc contactor 2. In the event of the arc occurrence, compressed gas inside the compression chamber 6 is injected through a nozzle 8 toward an arc, thereby extinguishing an arc and breaking (cutting off) a current.
The circuit breaker repeatedly performs a closing operation and a trip operation so as to maintain and break a conducted current, respectively. Here, the circuit breaker has to be operated with a normal speed. However, the circuit breaker may not maintain a normal speed due to load increment between inner contacts by repeated operations, and due to particle generations by friction.
FIG. 3 shows another example of the circuit breaker. Referring to FIG. 3, reference numeral 11 denotes a fixed side supporting plate, 12 denotes a fixed arc contactor, 13 denotes a gas injection nozzle, 14 denotes a movable arc contactor, 15 denotes a gas injection supplementary nozzle, 16 denotes a movable side supporting plate, 17 and 19 denote wear rings, 18 denotes a contact spring for conduction, 20 denotes a puffer cylinder, 21 denotes a movable arc contactor, and 22 denotes a cylinder rod.
Referring to FIG. 3, the wear rings 17, 19 and the contact spring for conduction 18 are fixed to the movable side supporting plate 16, and come in contact with the puffer cylinder 20 vertically reciprocating in the movable side supporting plate 16. As a result, as the gas insulation circuit breaker is repeatedly operated, marks or particles may occur on the surface of the puffer cylinder 20 due to friction between the puffer cylinder 20 and the contact spring for conduction 18. This may badly influence on a normal speed of the circuit breaker.